Car Air Conditioning Help

[Corey_lax]

Well tis the season of failing air conditioners. My Ram truck, my Matrix, and my wife's Kia all had issues. I knew nothing about AC systems a month ago and I'm learning lots lately. The Kia is fixed, and now I'm sorting through issues on my 2006 Toyota Matrix. The AC starts blowing cold when engine is cold and then warms up over time as the engine warms up until the compressor eventually shuts off. Here's what I've done:

• Checked fuses and relays --> All good
• Compressor turns on properly. Clutch gap is .6mm
• Refrigerant levels are good.
• Last night I started the car when the engine was cold. Ambient temperature was 18C/64F. The low pressure side started at 30psi, and high side started at 200 psi. After 20 minutes of idling, the low pressure side was very close to 0psi, and high side dropped to 170psi. What would cause the pressure to slowly drop like that? The compressor stayed running even at 1psi
• This morning I started the car when engine was cold. Ambient temperature was 13C/55F. Low side was at 18psi, high side was 170psi.

Why would the pressure drop as the engine warms up and the compressor is still running normal?
I think condenser might have a clog in it. It was warm in the passenger side upper corner, but very cool everywhere else. I'm not sure if this is normal.
I saw a small leak on the top of my radiator, so If I swap that out, I might just swap the condenser out at the same time.

Who on here knows how these magical air conditioning systems function?

 

[kingblazer84]

Hey corey have you Evac'd the system with a proper automotive ac machine to see how much charge is truly in the system and also vac pulled the system? It sounds to me like its low, even with the pressures dropping low slowly its acting like it doesnt have enough refigerant in the system to keep compressing therefore not keeping cool air coming to the vents. Rec/Dryer desiccant bags can plug up with crap over time and contaminated systems (Redtek filled) will cause issues as well.

 

[Corey_lax]

Hey corey have you Evac'd the system with a proper automotive ac machine to see how much charge is truly in the system and also vac pulled the system? It sounds to me like its low, even with the pressures dropping low slowly its acting like it doesnt have enough refigerant in the system to keep compressing therefore not keeping cool air coming to the vents. Rec/Dryer desiccant bags can plug up with crap over time and contaminated systems (Redtek filled) will cause issues as well.

I haven't evac'd it yet. I try to avoid shops whenever possible haha. I've even considered buying a vacuum and tank to avoid going to a shop. I know you'll hate to hear that LOL. But for these issues, I'll probably have to bring it to a shop with the proper equipment.

 

[CIVANO]

have you tried this?

 

[Corey_lax]

have you tried this?

View attachment 92925

I tried a version of those cans and no luck. I was hoping to just be low on refrigerant but it's not the case.

 

[kingblazer84]

I tried a version of those cans and no luck. I was hoping to just be low on refrigerant but it's not the case.

yeah you'll have to see a shop sorry my friend without proper diag equipment its hard to really narrow down AC issues and without a visable failure point. Im concerned if you have added a aftermarket sealant/refrigerant like above you might have to get the whole system flushed out before any shop even touches it! The reason is that those cans contaminate the whole ac system and can damage the very expensive machines we use to pressurize and vac pull and I know our shop we wont even do ac diag without it being completely flushed prior if the customer had prior introduced redtek or another aftermarket sealant.

 

[InterMechanico]

 

[Enniberg]

Took my 2006 GMC Duramax to a shop last week to have the AC fixed - it was not working when I bought the truck a couple of years ago.
Nitrogen purge, AC Evac, leak test and recharge $479.67 + tax. Blows ice cold now.
I have tried those cans on other vehicles in the past and never had any lasting success with it.

 

[Deejray]

Based on pressures you indicate and the way they change it's probably a restriction. likely the metering device or filter drier is plugged.

 

[Maxpri]

Took my 2006 GMC Duramax to a shop last week to have the AC fixed - it was not working when I bought the truck a couple of years ago.
Nitrogen purge, AC Evac, leak test and recharge $479.67 + tax. Blows ice cold now.
I have tried those cans on other vehicles in the past and never had any lasting success with it.

I just did mine with those cans and it’s back to normal now, the lack of lasting success sounds like there was probably a leak in the system. They have sealant cans which you can put it as well to stop leaks. Just my 2c

 

[Corey_lax]

Based on pressures you indicate and the way they change it's probably a restriction. likely the metering device or filter drier is plugged.

That’s what I was thinking. I assume I have to evacuate all the refrigerant to change the drier? It’s easy accessible from underneath on the condenser

 

[Corey_lax]

I just did mine with those cans and it’s back to normal now, the lack of lasting success sounds like there was probably a leak in the system. They have sealant cans which you can put it as well to stop leaks. Just my 2c

I’m never a fan of the stop leak stuff. I just put a regular r134a can in when I tried it a couple weeks ago. All the stop leak stuff can cause more problems than it solves

 

[Deejray]

That’s what I was thinking. I assume I have to evacuate all the refrigerant to change the drier? It’s easy accessible from underneath on the condenser

Yes would have to pull the charge to change it out. It's a good start as it's good practice to change the drier when opening the system to atmosphere. Do you have a vacuum pump for after you're done?

 

[Corey_lax]

Yes would have to pull the charge to change it out. It's a good start as it's good practice to change the drier when opening the system to atmosphere. Do you have a vacuum pump for after you're done?

Not yet but I’ve been browsing the cheap ones on Amazon. And they sell tanks for around $100 to recover the refrigerant.

 

[Viking]

Low side static pressure should be close to ambient temperature. To me it seems like you have a low charge, (small leak) and possibly a sticky thermal expansion valve. Putting dye in the system will help find small leaks without using nitrogen or sucking it down in a vacuum. After the dye has been run in the system for a couple days just look at all the components and connections with the same black light you would use to charge up your flashers.

 

[Corey_lax]

Low side static pressure should be close to ambient temperature. To me it seems like you have a low charge, (small leak) and possibly a sticky thermal expansion valve. Putting dye in the system will help find small leaks without using nitrogen or sucking it down in a vacuum. After the dye has been run in the system for a couple days just look at all the components and connections with the same black light you would use to charge up your flashers.

Yeah I guess I should put a dye in before draining everything. I figured there wasn’t a leak because in my mind, all of the gas should have escaped by now if there was a leak

 

[Enniberg]

I just did mine with those cans and it’s back to normal now, the lack of lasting success sounds like there was probably a leak in the system. They have sealant cans which you can put it as well to stop leaks. Just my 2c

I did just that with my 1991 GMC a few years ago - put in the can stuff, worked great for a little while, until it leaked out, then put in the sealant stuff and filled again with a similar outcome. That instance and other instances where I have attempted to fix my vehicles, just to have to pay a professional to fix my own fixing has taught me that I am saving money and grief by just taking it straight to someone who knows what they are doing and stands behind it, LOL

 

[Corey_lax]

I did just that with my 1991 GMC a few years ago - put in the can stuff, worked great for a little while, until it leaked out, then put in the sealant stuff and filled again with a similar outcome. That instance and other instances where I have attempted to fix my vehicles, just to have to pay a professional to fix my own fixing has taught me that I am saving money and grief by just taking it straight to someone who knows what they are doing and stands behind it, LOL

Ask me in a couple weeks how I feel about DIY air conditioning repairs haha.

 

[noluck]

diy only works if you find and repair the leak, or pressure switch/cycling switch that failed, then re fill the system. if you rely on sealers you will be fixing again

 

[Corey_lax]

diy only works if you find and repair the leak, or pressure switch/cycling switch that failed, then re fill the system. if you rely on sealers you will be fixing again

I never use sealers so no worries there. I ordered a vacuum pump. I don't even think there's a leak in the system or it should have been very low on pressure over the last couple months IMO.